This invention teaches improvements to portable hoists that are mountable to vehicles, building structures, carts, trailers, and the like. Examples in prior art are abundant and include teachings by Harr and Cary who introduce portable cranes in U.S. Pat. Nos. 5,752,799 and 5,993,137. Kruse teaches a in U.S. Pat. No. 6,007,289 that mounts into a receiver hitch and uses a jig to stabilize and increase the lifting capability of a hoist that is designed for powered mobility chairs. Williams teaches a portable mobility chair crane in U.S. Pat. No. 6,830,423 that engages a vehicle receiver adapter. Robinette teaches a low-pivot-point lift in U.S. Pat. No. 5,211,526 that does not have a hinge point.
Spitsburgen teaches a portable lift in U.S. Pat. No. 6,499,610 for medium to heavy applications. The '610 apparatus is readily assembled before each use and can be disassembled after use for easy storage. The Spitsburgen lift is mountable to vehicles, equipment, trailers, and building structures. Griffith teaches recoverable installation of a hitch hoist that is suitable for heavier objects in Canadian Patent 2,108,107. Davis teaches a multi-purpose hoist in U.S. Pat. No. 5,749,697 with top and bottom components mate together during assembly. Likewise Barger teaches a portable crane in U.S. patent application Ser. No. 10/657,029 that is adaptable to shop work benches, vehicles, and other stable structures. Amato teaches a swingable boom-type portable crane in U.S. Pat. No. 4,881,864 that engages the receiver hitch of a vehicle.
Compton teaches a collapsible hoist in U.S. Pat. No. 6,152,675 that has a sufficiently high center mast to elevate hunting game; the hoist is assembled, installed, and subsequently removed between uses. A collapsible hoist taught by Perkins in U.S. Pat. No. 6,578,722 also engages a vehicle receiver hitch and has a telescoping mast that is able to achieve a sufficient height to raise tall objects. Phillip and Angel teach similar game hoists in U.S. Pat. Nos. 6,705,821 and 7,201,552.
Other exemplary embodiments are described in U.S. Pat. Nos. 6,478,528, 6,386,820, 5,520,498, 5,445,487, 5,014,863, 7,300,238, 6,981,834, 6,860,703, 6,138,991, 6,089,431, 6,082,561, 5,810,547, 5,788,095, 5,800,117, 5,662,451, 4,417,665 and US patent application publication 20110206488.
All examples and combinations of examples of portable cranes found in prior art rely on assembly before use and disassembly after use. Among the above listed examples, the '675, '522, '722 and '821 cranes share the additional common drawback that they do not pivot. US Patent Application US2009/0067968 A1 also teaches a portable crane that requires assembly between uses and does not pivot. Prior art is quick to point out that each phase of assembly can be performed in as little as 2 minutes.
The present invention unveils a notable improvement by teaching a hoist that unfolds into a usable state in as little as 2 seconds and folds into a stowed state just as quickly. No assembly is required to transition the present invention in an operable state and no disassembly is required to revert the present invention back into a stowed state. To achieve this improvement over prior art the present invention combines a low profile pivoting hinge with latching and stopping surfaces, a hinge mounted mast with latching and stopping surfaces, and a hinge mounted boom with latches and stopping surfaces that automatically lock the hoist into operable and stored states as it is folded or unfolded. Nothing found in prior art or any combination thereof is seen to describe the present invention.